Systems of this type are used in particular to fasten rails on a wooden sleeper in a simple manner. The purpose of the base plate, which is generally made of a steel as a hot-rolled or forged product, is in this case to transmit uniformly onto the sleeper the loads which occur when a railway vehicle travels over the fastening point formed by such a system.
In order to ensure rapid and at the same time particularly simple assembly, the base plates are fastened on a wooden sleeper during assembly conventionally with nails. The rail is also fastened on the base plate generally with nails which are struck through corresponding openings molded in the base plate. The nail head has in this case a portion protruding laterally relative to its shank. When it is struck into the wooden sleeper, the nail head is oriented in such a way that it rests, when fully struck in, on the rail foot and holds down the rail.
Fastening systems of the type described hereinbefore fulfil their purpose in track installations on which trains travel at a comparatively low speed. However, they do not meet the requirements of modern high-speed trains.
A large number of fastening systems which are able reliably to accommodate the dynamic loads occurring in high-speed trains are known. A typical example of a system of this type is offered by the Applicant under the name “System KS”. Information about and an installation guide for this system are available from the URL “www.vossloh-fastening-systems.de”.
The System KS has a base plate which is made of steel and is also referred to by experts as a “rib plate”. The base plate has a central portion which is laterally delimited by a respective rib. The distance between the ribs corresponds in this case to the width of the rail foot of the rail to be fastened. A respective opening, positioned in which is a screw bolt, the threaded portion of which points away from the upper side of the respective rib, is molded into the ribs from the free upper side thereof. In addition, through-openings, through which the screws, which serve as fastening elements, can be screwed into the respective substrate, are molded into the base plate.
In the System KS, the holding forces required in order securely to hold the rail are generated by means of W-shaped tensioning clamps, each of which is mounted on one of the ribs. The loop-shaped central portion of the tensioning clamps is in this case placed around the threaded portion of the screw bolt inserted into the respective rib and braced against the base plate by means of a nut screwed onto the screw bolt. In this case, the spring arms of the tensioning clamp are supported with their free ends on the rail foot and thus resiliently hold down the rail. The resilient holding brought about in this way of the rail has the advantage that the fastening has a defined flexibility. This ensures that the rail is not excessively loaded even under the action of high dynamic forces.